The present invention relates generally to the field of ski construction and in particular to a new and useful ski apparatus capable of freely gliding on snow as opposed to skidding or scraping across the snow. The new ski has a uniquely narrow waist width, and a single- or double-bladed wing can be mounted above the primary ski for providing a secondary turning radius. The ski of the invention is substantially symmetrical with the narrow waist positioned midway along the length, and the tip and tail having similar shape and flexural characteristics. Additionally, the ski may include a bi-level suspension system with a boot binding assembly above the level of the running surface, and a quick release system for detaching the ski body from the suspension system and boot binding.
Recreational skiing as it is taught and practiced around the world is a skidding sport, as differentiated from gliding sports such as ice skating or in-line skating. Furthermore, the incline angle of a ski slope creates a downhill force that is typically up to five times greater than that necessary to propel the skier at the desired speed. Thus the basic essence of the sport of recreational skiing is speed control or constant braking.
In order to maintain speed and directional control, a conventional ski relies on the lateral friction generated between a ski slope surface and the ski edges as the ski skids, or slides, sideways relative to its longitudinal axis. The skier must therefore always have the skis oriented at an oblique angle relative to the downhill direction of movement. This requires the skier to be constantly alternating this angle from left to right of straight downhill in order to stay centered on the ski trail. This is a difficult and tiring movement.
In addition, graceful or controlled skidding requires a delicate balance in order to maintain the correct braking and directional forces with the snow. When too much lateral friction is generated, the skis and skier stop, and when there is too little friction, the skier effectively loses control of his direction and speed. Thus, the phrase, “catching an edge” used by a skier to justify falling down is accurate, since that is what occurs when the ski suddenly ceases to skid.
Early skis had substantially straight, parallel edges, and required greater skill from a skier. Modern skis are designed to have a long and wide shovel, or front portion, that helps start the skid, and a short and narrow tail that can easily complete the skid. And, the newest skis have increased width all along the ski length to provide a wider and more stable platform for skiers. In order to facilitate skidding or braking, the binding for holding a skier's boot to the ski is conventionally mounted toward the rear, or tail, of the ski.
In contrast, gliding sports, such as snow gliding, ice skating or in-line roller skating are designed to eliminate lateral friction or skidding with the supporting ground surface, allowing the person to maintain their momentum in the direction of travel with very little effort. Steering or controlling direction is accomplished by simply leaning or tipping in one direction or the other. The forces at work in gliding sports do not normally result in skidding nor require as much physical strain by the participant as skidding sports, such as snow skiing.
Gliding, in particular, is designed for recreational skiers who are not interested in the challenge or danger of conventional downhill skiing which requires control of speed on steep hills by regularly turning in skid turns on hard snow or plowing against soft snow.
Compared to gliding, a downhill skier must work harder because he is almost always moving (skidding) in a direction other than that to which the skis are pointed, requiring repetitious shifts in weight and body position between left and right stances in order to maintain the general downhill direction. Glide skiing involves gliding only in the direction to which the glider skis are pointed, and can provide a relaxing thrill gliding down an appropriately inclined hill rather than the stressful or feared descent that is typical of conventional skiing.
Unlike conventional skiing, glide skiing does not require constant braking and frictional speed control. Changes in direction do not require poles or skidding. Only gliding is necessary. Whereas conventional skis are designed to skid and not “catch an edge”, gliding skis mandates an opposite approach that prevents skidding and encourages aggressive edge engagement. Accordingly, a ski construction and design is needed for facilitating gliding on snow, which is different from ski construction found in the prior art.
Modern skid-type ski construction is generally taught in many patents. U.S. Pat. No. 5,405,161, for example, discloses a ski having a waist portion which can be as narrow as 40-50 millimeters (2 inches or less), but preferably 55-70 millimeters wide, and ends which are between about 70-115 millimeters wide. The ratio of the width of the waist portion to the shovel is between 1:1.55 and 1:2.25. The shovel must be at least 1.05-1.43 times the width of the tail. Thus, the shovel and tail of the ski are not symmetrical. The boot bindings are not centered on the ski and are positioned closer to the tail than the shovel of the ski.
U.S. Pat. No. 5,727,807 teaches a ski having a waist portion comprised of two different sections to provide better edge control. A center portion of the ski bottom surface is covered with serrations. Unserrated edge portions of unknown width extend around the entire center portion; the total width of the ski is not disclosed.
U.S. Pat. No. 382,254 discloses a snow skate type ski having upswept tips and backs. The body of the ski has parallel sides, however, so that the ski does not taper inwardly at the waist where the boot is secured. The ski is described as being about 4 inches wide.
Other patents teach particular mountings for the boot bindings.
U.S. Pat. No. 5,984,344 discloses an elongated carrier for a binding connected to the ski in about the middle of the carrier. A pivoting connection of the carrier to the ski is disclosed, with damping bellows connected to each end of the carrier. The bellows and other damping mechanisms disclosed can be adjusted hydraulically to provide control over the stiffness of the ski in the binding region. The carrier is provided to permit adjustment of the bending properties of the ski and improve the control. The patent indicates that when the ski boot is elevated above the ski body surface, a high degree of edging is possible, giving greater control and stability.
U.S. Pat. No. 5,647,353 teaches a ski having a floating binding plate damped by a fluid pressure medium for modulating forces exerted on the ski. The pressure can be adjusted on the fly, if desired, to control the effect of the force modulation provided by the floating binding plate.
U.S. Pat. No. 5,671,939 illustrates a ski having the bindings mounted to permit continuous flexion of the ski body, even under the binding, so that the ski can form a continuous curve. The bindings are mounted to a plate movably secured to the ski. The relative spacing of the bindings is maintained when the ski is flexed by the pins connecting the plate to the ski moving forward and back within mounting slots secured to the ski body. The plate is secured at both ends, so that pivoting movement relative to the ski is not possible.
A binding support in the form of an elevated plate is disclosed by U.S. Pat. No. 5,915,719. In one embodiment, the support is connected at its center on a pair of feet secured to the ski. The ends of the support may have compressible shims inserted between the support and ski.
Still other patents disclose devices for improving the control over turning of a ski or snowbard.
U.S. Pat. No. 5,462,304 discloses a snowboard having interchangeable, dual-acting edges which extend continuously along the outside length of the active board edge. The interchangeable edges are provided to make repair and maintenance easier, as well as providing a simple method for adapting the snowboard to the skiing surface conditions. The interchangeable dual-acting edges each have a pair of control edges, one elevated above the other. The lower, first edge is oriented facing inwardly toward the board center, while the upper, second edge faces outwardly. The first edge contacts the skiing surface during level, flat riding, while the board be rolled onto the second, elevated edge in a sharp turn. The second edges act similar to a governor and provide stability in sharp turns so that the snowboarder can return to the first, lower edges without falling. The orientation of the edges is arranged to prevent the second edges from creating instability when the board is flat.
U.S. Pat. Nos. 5,040,818 and 5,462,304 each describe a ski for a vehicle such as a snow-mobile which has an elongated cylindrical wear bar mounted to the bottom middle of a center concave portion and a pair of horizontally extending concave surfaces vertically offset above the center concave portion. The horizontally extending concave surfaces are provided as primary steering surfaces and extend along the length of the ski on each side. The wear bar is provided to the first concave surface for when the ski is running on icy surfaces. The snow-mobile skis described do not have any secondary turning edges or surfaces.
U.S. Pat. No. 6,394,482 teaches a ski having an asymmetrical shape for improving the turning characteristics of the ski, but which lacks second turning edges. The ski shovels are shaped to have a slightly concave inner edge and an outer edge which curves outwardly to a point and then back in again toward the ski waist. The position of the point on the outer edge makes the curvature of the outer edge more closely match the curvature of the inner edge of the second ski during a turn, so that greater control and smoother turns are achieved.
As noted above, conventional skiers are always subject to a delicate balance of forces when their skis skid; a fall is likely when that balance is upset by changing friction conditions. The balance of forces is easily upset by minor changes in snow consistency which can cause a skidding ski to suddenly grab or engage the snow, or conversely, lose all friction when ice is encountered.
In contrast, snow gliding does not involve a frictional/skidding relationship with the snow. Instead, a glider ski has positive engagement with the snow or ice surface at all times. Changes in surface consistency are virtually irrelevant to a glider ski because it is not subject to a delicate balance and does not depend on lateral skidding. A glider ski user will generally not lose their balance due to changing surface conditions.
In glide-skiing, a skier is essentially always riding on an edge, similar to an ice skater, but without the need to constantly shift weight and stance to cause the edge to dig into contact with the snow. Gliding skis require certain design elements to optimize maneuverability, control, and engagement with the snow. These design elements are generally opposite and non-intuitive from the requirements for conventional skis. One design element of particular importance is the width between the edges at the waist. The waist portion is traditionally the narrowest point across the ski width and is often where the boot binding is mounted.
In conventional ski design, there has been a growing trend for a wider waist design in commercially available recreational skis. Today, most such skis have a waist width of about 70 mm. This wider waist creates a sense of stability when the ski is flat on the snow. Such a wide design, however, is counterproductive to ski edge engagement. That is, it is more difficult for a skier to roll onto the edges for making carved turns; but, this can be a benefit to maintaining a controlled skid and for skiers who frequently “catch an edge” and fall.
A glide skier contrarily wants to achieve the opposite result—the glider ski wants to catch the edge in positive contact with the surface, and then continually ride the edge without skidding. Therefore, a waist design is needed for glide-skiing so that the glider ski engages the snow similar to an ice skate blade.
Furthermore, the technique of conventional skiing involves step by step sequences of ski movements. The design of conventional skis parallels the sequences of movements by being asymmetrical. The front of the ski is optimized for turn initiation, while the tail and rear-biased boot position are designed for an easy skid at completion. In keeping with these design criteria, the width dimensions and flex characteristics of conventional skis vary between the front and rear of the ski. Unlike this sequential step method, glide-skiing is a continuous, fluid motion, and thus the glide skier has a symmetrical and balanced shape and construction.
The rigid mounting of ski boots on conventional skis precludes the middle section of the ski where the boots are mounted from flexing. The combination of the boot and binding restricts ski flexing to the front and tail sections only, keeping the middle section relatively straight and flat. This rigidity can help the skier shift weight for entering a skid turn.
A glider ski, on the other hand, must have substantially continuous flexural capability along the length of the ski to achieve positive engagement with the snow. Ideally, the glider ski shape conforms substantially to an arc when making turns. Therefore, a ski construction is needed to ameliorate the negative influence of the boot/binding on the flexibility of the glider.
The turning radius of both skis and gliders is determined by the shape of the running surface. Typically, the front and rear of the ski are wider than the middle of the ski under the boot. For a given pair of skis, the manufactured dimensions predetermine the turning radius. A skier must choose a specific pre-manufactured turning radius, and must remain locked into that turning style. This is extremely restrictive for both skiers and glide skiers, particularly when using glider skis that positively engage in the snow. Different conditions may make different turning radii desirable. There is a need to provide more versatility in turning radius.